Temperature control apparatus



Sept. 23, 1958 H. c. STEARNS TEMPERATURE CONTROL APPARATUS OriginalFiled April 25, 1956 3 Sheets-Sheet 1 INVENTOR.

Sept. 23, 1958 H. c. STEARNS TEMPERATURE CONTROL APPARATUS OriginalFiled April 25, 1956 3 Sheets-Sheet 2 INVENTOR- H. C. STEARNSTEMPERATURE CONTROL APPARATUS Original Filed April 25, 1956 Sept. 23,1958 Ill/fl I ///(f/ H CINgViNTOR. 4/ 7 W BY United States Patent OTENIPERATURE CONTROL APPARATUS Harry C. Stearns, Glen Ellyn, Ill.

Original application April 25, 1956, Serial No. 588,618, now Patent No.2,822,794, dated February 11, 1958. Divided and this application March25, 1957, Serial No. 648,061

Claims. (Cl. 123-122) The invention relates to temperature controlapparatus for the intake air for internal combustion engines.

The main object of the invention is to prevent so-called icing occurringin the carburetor brought about by either cold air or air having a highdew point. Heretofore, special exhaust heated manifolds have been usedto warm the intake air before its passage to the carburetor, but thereare drawbacks to such arrangements as in extremely hot weather vaporlock is aggravated and also the heavy mass of the manifolds warm upslowly so that the necessary heat was not obtained soon enough to meetthe requirements of the accumulating front in the carburetor so thatstarving of the engine after starting was a typical result. According tothe present invention prior difficulties have been overcome by takingheat from a thin walled exhaust pipe section or stove to secure aprompter heating of the air and automatically controlling the amount ofthis heated air by thermostatic valving to provide intake air of atemperature that will meet seasonal conditions.

This application is a division of my application Serial No. 580,618,filed April 25, 1956, now Patent No. 2,822,794, for Temperature ControlApparatus, and relates more particularlytothat form of apparatus inwhich the valves controlling admission of heated air and other air atambient temperature are linked together and controlled by a thermostatand means responsive to the demands of the engine are provided forvarying the action of the thermostat.

The invention further consists in the several features hereinafter setforth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a perspective view of a tractor equipped with apparatusembodying the invention, parts being broken away;

Fig. 2 is a view partly in section of temperature control apparatusembodying the invention as installed on other engine parts;

Fig. 3 is a plan view of parts of the apparatus, parts being broken awayand parts being shown in section;

Fig. 4 is a vertical sectional view taken on the line 4--4 of Fig. 3;

Fig. 5 is a view similar to Fig. 2 showing certain modifications, partsbeing broken away;

Fig. 6 is a plan view-of the modified form of apparatus, parts beingbroken away and parts being shown in section;

Fig. 7 is avertical sectional view taken on the line 7-7 of Fig. 6.

In Fig. l I have shown a tractor T having an engine E providedwith anexhaust pipe 5 and an intake 6. In Fig. 2 the exhaust pipe 5 is shown asconnecting with theexhaust pipe 5 is shown as connecting with theexhaust manifold 7 for the engine and the intake pipe 6 connecting withan air cleaner 8 whose outlet is connected by a I pipe 9'withthe inletto a carburetor 10 that is connected to the engine inlet manifold 11.The apparatus. embody- 28 acting to tend to close the valveasthetemperature of 2,853,065 Patented Sept. 23, 1958 ing the invention areparts adapted to be mounted and supported on the exhaust pipe and theintake pipe.

The exhaust pipe 5 is provided with the usual mufiler M which as is wellknown is formed of fabricated sheet metal parts of thin walled sectionso that heat is rapidly dissipated therefrom. Over this mufller and theupper end of the exhaust pipe I mount a tubular housing 12 secured inposition by equidistantly disposed set screws 13 or other suitable meansengaging the muflier and spacing the sides of said housing and its topfrom the mufller and a portion of the pipe 5 to form a heating chamber14.

From the housing 12, a pipe 15 leads to a flanged top opening 16 of avalve containing air inlet housing 17 which has a flanged bottom opening18 fitting the upper end of the air intake pipe 6.

The housing 17 has a side opening 19 covered by a screen 20.

Under the suction action of the engine, air passes upwardly through thechamber 14 and pipe 15 to the housing 17 and thence through pipe 6,cleaner 8, pipe 9 to the carburetor 10 which delivers it'sfuel mixtureto the intake manifold 11. In passing through the chamber 14 the airtakes on heat given 01f by the exhaust heated muffler M so that it willbe heated sufliciently so that a mixture with the fuel will be formed inthe carburetor without danger of icing.

In order to control the temperature of the intake air to take care ofseasonal changes, a flap valve 21, controlling passage of heated airthrough the opening 16, ismounted on a lever arm 22 pivoted on a shaft23 mounted in the housing 17. This'valve is opened 'or closed dependingupon the temperature of the heated air under the control of athermostatic means here shown as a bimetallic element 24 in the form ofa lever pivotally'mounted in: termediate its ends on a pin 25 mounted inthehousing 17. The outer end of the longer arm of the lever is adaptedto contact the valve and the shorter arm of the lever is adapted to beengaged by an adjusting scr'ew 26 mounted in the housing 17' andprovided with a lock nut 27, this screw acting to impart a variableinitial tensioning contact between said element 24"and the valve 21,which is op'enable under the suction effect of the engine in varyingamounts depending upon the effect of the incoming heated air on thethermostat 24, this member bending and tending to close the valveas thetemperature of the-exhaust heated air increases.

A curved flap valve 28 controls passage of unheated air through theopening 19 and is mounted on a lever arm 29 pivoted on a shaft 30mounted in the" side of'the housing. This valve is normally urged to aclosed position by a leaf spring 31, hearing thereon at one end, pivotedon the shaft 30 intermediate its ends, and adjustably engaged at itsother end to vary its pressure on the arm 29 by load adjusting screw 32mounted in the housing 17 and secured in set position by a lock nut 33.The supply of intake air controlled by this valve is supplemental to thesupply of heated air controlled by the valve 21. As the-bimetallicelement'24" tends to close the valve 21, the suction effect of theengine acts to open the valve 28 so that a tempered mixture of warm. andcooler air is supplied to the carburetor to meet operating conditions;

but under some conditions it is desirable to control-the maximum openingmovement'of the valve 28, and for this purpose a thermostatic meansacting on thespring the air drops, it being noted that as the ambienttemperature drops so will the temperature in the housing drop.

With the above construction, the valve 21 is controlled entirely by thetemperature of the air entering the housing 17 and on starting of theengine opens up to the dotted line position shown in Fig. 4, and if theoutside air is cold, it may stay in this position or be partly shut bythe action of the thermostat 24 depending upon weather conditions, theair furnished to the engine through the opening 16 being sufficientlywarm to improve vaporization in the carburetor and to preventcondensation on the cold wall of an unheated manifold. Then when thethrottle is opened wide under heavy load, the thermostat adjustmentshould be such that the temperature of the inlet will prevent icing butnot much above it to develop high volumetric efiiciency. Preferably, thevalve 21, under the action of the element 34, will not close off theopening 16 below a temperature of one hundred twenty degrees,Fahrenheit. In somewhat warmer weather this adjustment of the thermostat24 closes the valve 21 somewhat and permits outside air to come into thehousing 17 through the opening 19 as the valve 28 opens under suction sothat a mixture of warm and cool air is furnished the engine, and in hotweather the valve 21 may be shut or nearly shut and the engine air takenin through the side opening 19. The by-pass valve or valve 28 is heldclosed by the spring 31 until about a quarter pound per square suctionpressure drop causes it to open gradually to a full open position atthree-eighths pound per square inch suction pressure to handle the fulldemand of the engine. When the air temperature is at seventy degreesFahrenheit, the element 34 will begin to contact the spring 31 in theopen position of the valve 28 and will have this valve well closed down,as shown in Fig. 3 when the outside air is at fifty degrees Fahrenheit.Thus when the ambient temperature is seventy degrees or higher, the

valve 28 will function entirely by a pressure drop across it, and sincethe valve 21 will not close off below one hundred twenty degreesFahrenheit, at lower air demands as in idling or slightly above, the airtaken through the carburetor will approach this upper value. Since thearea of the by-pass port or opening 19 is considerably greater than theport or opening 16, although either is large enough to handle fullengine demand without undue drop, on heavy air demands the flow willfavor the port 19 when the ambient temperature is above seventy degrees.

It is to be noted that due to the inertia of the valves 21 or 28, whenthe engine load is increased suddenly with a greater demand for fuel,these valves are of a weight and mass to act like instantaneous chokesto cause a greater amount of fuel to be supplied to the enginemomentarily.

Instead of a separate thermostat for each valve, the valves may bejointly controlled by a single thermostat, preferably subject tomanifold pressure control as shown in Figs. to 7.

Referring to Figs. 5 to 7, the flanged top opening 36 of a housing 37connects with the pipe 15 and its flanged bottom opening 38 connectswith the air intake pipe 6. The housing has a bottom opening 39 coveredby a screen 40.

A flap valve 41 carried by an arm 42 pivotally mounted at 43 on abracket 44 secured to the housing 37 controls the passage of heated airthrough the opening 36.

A flap valve 45 controls passage of unheated air through the opening 39and has an arm 46 pivoted on a shaft 47 mounted in a bracket 48 carriedby the bottom of the housing.

A lever 49 has a forked lower end 50 pivoted on said shaft 47 and at itsupper end is pivotally connected at 51 to one end of a lengthwiseadjustable rod 52 having sections connected by an adjustable turnbuckle53. The other end of the rod 52 is pivotally connected at 54 to head end55 of a flexible metal bellows 56 whose other 4 end is anchored againsta side portion of the housing 37. A port 57 in the housing connects theinterior of the bellows with a pipe 58 leading to the engine manifold11.

The valves 41 and 45 are connected together by a link 59 pivotallyconnected at its ends to said valves.

A bimetallic element 60 of looped form has one end 61 pivotally anchoredto the valve 45 and its other end carries a transversely extending pin62 whose extensions work in the slots 63 of a pair of oppositelydisposed links 64 pivotally carried by a pin 65 mounted intermediate theends of the lever 49. The metal of the element 60 having the highercoefficient of expansion is on the outside of the loop.

The element 60 is so arranged that at any temperature below 50 F. itwill expand and close the cold air valve 45. In so doing, the valve 41admitting warm air is held open. This condition prevails regardless ofthe slots 63 and the position of anchorage of the lost motion links 64due to changes in manifold pressure. This position is not shown in thedrawings, but in this position the pin 62 is at the ends of the slots 63near the points of anchorages of the links 64.

As the temperature of the intake air rises above 50 F. because of heatimparted to it by the exhaust as previously described, the element 60first becomes ineffective to close the cold air inlet or tends to openthe valve 45 when manifold pressures are high, but as soon assubstantial manifold vacuum develops, the element 60 will let the coldair valve 45 close. As the temperature of the intake air rises, a higherand higher vacuum in the manifold 11 is required in order to close thevalve 45, until finally a temperature is reached where the element 60will have contracted sufiiciently to open the valve 45 and close thewarm air inlet valve 41 regardless of the amount of vacuum prevailing inthe manifold.

It may be of advantage to so arrange the parts that the latter extremecannot be reached and that some warm air will always be admitted even athigh ambient temperatures whenever the manifold vacuum becomes veryhigh. The purpose of such a relation of the valves 41 and 45 relative toeach other is to bring to the throat of the carburetor even in hotweather under idling and low powered conditions a warm air mixture suchas would produce a maximum vaporization of the fuel as distinguishedfrom simple atomizing. This effect is sought because at low throttlesettings, low power, or idling conditions atomization is erratic andincomplete, and there is a tendency for liquid fuel to accumulate in thecorners of the inlet manifold and other places producing uneven runningof the engine.

When properly adjusted, if for any reason the high temperatureinterferes with engine operation at low speed, manifold pressure willdrop and the cold air valve 45 Will be immediately opened to remedy thissituation. On the other hand, with the engine running properly at lowpower on warm air, if a sudden demand is placed on the engine for powerand the governor opens the throttle wide, the valve 45 will again beimmediately opened since the vaporizing effect of the warm air stream isno longer of advantage due to the higher air velocity which is thenadequate to atomize the fuel.

The bellows 56 is normally urged to an expanded position by a spring 66when atmospheric pressure is prevailing in its interior. As manifoldsuction increases, the bellows contracts against the outward expansiveforce of the spring. The loading of spring 65 should be such that thenormal travel of the bellows is complete over the normal range ofmanifold pressures. The effective length of the rod 52 is adjustablethrough the turnbuckle 53 so that the valves 41 and 45 will occupy thepositions intended at the temperatures and manifold pressures which aredesired.

In the device shown in Figs. 3 and 4 the valves 21 and 28 act totransfer from a cold to a hot air supply at an arbitrarily chosentemperature range, but even in cold weather, if there is sufiicientsuction, some cold air will be admitted to the housing 17. Even in Warmweather if there is suflicient suction, some warm air will be drawn in.This is due to the fact that both valve 21 and 28 open inwardly againstthe resilient restraint of their bimetal elements. In the form of Figs.5 to 7 the two valves 41 and 45 are counterbalanced against one anotherso far as suction effects are concerned, and because of this thesevalves are not responsive to suction except in so far as the bellows 56alters the biasing effect of the element 60. Manifold pressures in thisinstance are taken beyond the carburetor rather than on the air inletside, and this type of suction is not the same as the suction affectingthe valves of the first form. Manifold suction may be very high at lowthrottle settings. The suction that aifects the first form of device canbe high only at large throttle openings with the engine turning atfairly rapid speed. The differences in performance are mainly due tothis factor. It is im portant to bear in mind that devices of the typedescribed are intended primarily for use on governed engines, and withsuch engines suction in the heat control device itself may be moreclosely related to power demand than manifold suction.

From the foregoing it will be noted that the valve arrangements hereinprotect against icing under all conditions and permit supplying aconsiderable elevated temperature to the air at partially open throttle.

I desire it to be understood that this invention is not to be limited toany particular form or arrangement of parts except in so far as suchlimitations are included in the claims.

What I claim as my invention is:

1. In a temperature control apparatus for the intake air of an internalcombustion engine having an inlet manifold, the combination of a housingconnected with the air intake of the engine, an exhaust heated airheater for supplying heated 'air to said housing, a valve controllingthe passage of heated air to said housing, a passage in said housingopen to atmosphere, a valve controlling air flow through said passage,connections between said valves for opening one valve while closing theother, and a thermostat mounted in said housing and acting as amotivator for said valves, and separate means responsive to the suctionpressure of air in said manifold to vary the action of said thermostat.

2. In a temperature control apparatus for the intake air of an internalcombustion engine, the combination of a housing connected with the airintake of the engine, an exhaust heated air heater for supplying heatedair to said housing, a valve controlling the passage of heated air tosaid housing, a passage in said housing open to atmosphere, a valvecontrolling air flow through said passage, each of said valves beingpivotally mounted in said housing for movement inwardly to an openposition, a link operatively connecting said valves to effect theiralternate opening and closing, a thermostat in said housing acting as amotivator for said valves, and separate means responsive to the demandsof the engine for varying the action of said thermostat.

3. In a temperature control apparatus for the intake air of an internalcombustion engine having an inlet manifold, the combination of a housingconnected with the air intake of the engine, an exhaust heated airheater for supplying heated air to said housing, a valve controlling thepassage of heated air to said housing, a passage in said housing open toatmosphere, a valve controlling air flow through said passage, each ofsaid valves being pivotally mounted in said housing for movementinwardly to an open position, connections between said valves foropening one valve while closing the other, a lever pivotally mounted insaid housing, means sensitive to manifold pressure for varying theposition of said lever, and a bimetallic thermostat in said housing andinterposed between said lever .and one of said valves acting as amotivator for said valves and capable under certain conditions of engineoperation to move independently of said lever.

4. In a temperature control apparatus for the intake air of an internalcombustion engine having an inlet manifold, the combination of a housingconnected with the air intake of the engine, an exhaust heated airheater for supplying heated air to said housing, a valve controlling thepassage of heated air to said housing, a passage in said housing open toatmosphere, a valve controlling air flow through said passage, each ofsaid valves being pivotally mounted in said housing for movementinwardly to an open position, connections between said valves foropening one while closing the other, a lever pivotally mounted in saidhousing, means sensitive to manifold pressure for varying the positionof said lever, a slotted link mounted on said lever, and a bimetalliclooped thermostat mounted in said housing and having one end pivotallyconnected to one of said valves and the other end connected to theslotted portion of said link.

5. In a temperature control apparatus for the intake air of an internalcombustion engine, the combination of a housing connected with theengine and having an inlet for heated air and an inlet for air atambient tem- References Cited in the file of this patent UNITED STATESPATENTS 1,017,572 Lund Feb. 13, 1912 FOREIGN PATENTS 868,897 France Oct.20, 1941

